1. Field of the Invention
The present invention relates to a code transforming apparatus and code transforming method.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. 2000-293413 discloses an invention in which a common part and a non-common part of a plurality of files on a storage medium are distinguished from each other, with file commonality information for the common part and the non-common part being stored for each file and the common part being shared among the plurality of files.
Briefly, in the technology disclosed in the patent document as mentioned above, instead of redundancy compression, a code format characteristic having a BOX structure is used to achieve reversible compression of files.
As an example of such a code format having a BOX structure, there is the one in which sharing/referencing is not defined in BOX information. Reference may be had to, for example, Annex B pp. 31-49, “Information Technology Digital Compression and Coding of Continuous Tone Still Images Requirements and Guidelines, Terminal Equipment and Protocols for Telematic Services, The International Telegraph and Telephone Consultative Committee”, Recommendation T.81, September 1992, International Telecommunication Union (hereinafter, “first non-patent document”). As another example, there is the one in which sharing/referencing is defined in BOX information. Reference may be had to, for example, 5.2.7 Shared Data, “Information technology-JPEG2000 Image Coding System-Part 6: Compound Image File Format, JPEG2000 Part 6 FDIS”, 9 Dec. 2002, ISO/IEC 15444-6 (hereinafter, “second non-patent document”), and 5.2.7 Shared Data, “Information technology-JPEG2000 Image Coding System-Part 2: Extensions, JPEG2000 Part 2 FDIS”, 8 Aug. 2001, ISO/IEC 15444-2 (hereinafter, “third non-patent document”). The term “BOX” indicates an object encapsulated in a file and having a binary structure. A code format targeted in the present invention is the latter code format in which sharing/referencing is defied in BOX information.
FIG. 22 depicts a JPEG syntax disclosed in the first non-patent document. As shown in FIG. 22, “Entropy-coded segments” 30 and “Entropy-coded segmentlast” 31 are synchronized with each other with “restart interval end symbol RST” 32 to form one “Scan1” 33, and “Frame” 34 is formed as an aggregate of these “Scan”, the aggregate being encapsulated with “SOI marker” 35 and “EOI marker” 36 to form a code format. However, in this code format, even there are a plurality of “Entropy-coded segments” of the same content in one file, the first non-patent document does not define at all a mechanism of sharing or referencing these segments.
FIG. 23 depicts a conceptual structure of a JPM (JPEG2000 Multi Page) file disclosed in the second non-patent document. In the second non-patent document, sharing/referencing of BOXes of “Contiguous Codestream Boxes” 37, “Metadata Boxes” 28, and other boxes illustrated in FIG. 23 are defined.
In the meanwhile, there may be the case where the same images are disposed in different sizes on the same page of a document or a common logo mark or the like is printed over a plurality of pages of a document. For such an image as a common logo mark, if one codestream is shared/referenced among all files of a document, the files can be made more compact. When a large amount of pages of a manual is created by sharing the load among a plurality of persons, the color phase of a logo mark and others may be slightly different for each section (page). If a codestream of one logo mark is shared/referenced among all files of the document, the files can be made compact and also the color phase of the logo mark and others can be made evenly. This is advantageous in appearance of the document.
However, in order to share/reference an object of a common logo mark, for example, it is not practical to manually search binary data of the logo mark for performing an operation of sharing/referencing.